This handout photo taken on December 12, 2018 and provided by South Korean Defence Ministry shows a South Korean officer (left) speaking with North Korean officers (right) during an inspection of the dismantled North Korean guard post inside the Demilitarized Zone dividing the two Koreas in Cheorwon. Soldiers from North and South Korea crossed into each other's territory peacefully for the first time on Wednesday, Seoul said. Photo: AFP

South Korea has ordered hundreds of soldiers manning the demilitarized zone (DMZ) on its border with North Korea to track and capture wild boars in a bid to prevent the spread of African swine fever, military officials said.

South Korea confirmed its seventh case on Thursday, just over a week after the virus was first detected and prompted authorities to step up disinfection measures.

The source of the outbreak has not been confirmed, but the virus has been found on hog farms near the border with North Korea, which reported an outbreak in May to the world body in charge of fighting animal diseases.

Troops and equipment were deployed this summer to monitor and trap wild boars suspected of carrying the virus, a South Korean military official told Reuters.

"We can't shoot them because it would be a violation of the armistice agreement," the official said, referring to the 1953 pact with the North that halted fighting but did not end the war and has governed the border ever since.

The 250-kilometer DMZ is also home to wild animals that thrive in the wooded no-man's land.

The animals may be deterred by fences and other barriers along the DMZ, the military official added.

The US-led United Nations Command (UNC), which helps oversee the DMZ, is not involved in containing the virus, the official said. The UNC did not respond to a request for comment.